Informally, the number is one followed by "one followed by "one followed by "one followed by "one followed by "one followed by "one followed by "one followed by ten billionzeroes" zeroes" zeroes" zeroes" zeroes" zeroes" zeroes" zeroes. It is also 10 pentated to 2, as \(n \uparrow^{k} n = n \uparrow^{k+1} 2\). The number's name is probably a reference to the SI prefix deca- for 10, which is itself derived ultimately from the Ancient Greek word δέκα, meaning 10.

In terms of recursion, decker is on par with the larger numbers giggol (10 tetrated to 100 = {10,100,2}) and grangol (E100#100), although decker is much smaller.